Meaning and mechanism
The horizontal scale represents one unit of time, and the vertical scale represents one unit of voltage. It is necessary to convert the repetition interval and height of the waveform from scale units to actual units.
The trigger aligns the screen’s reference point when it passes at the predetermined voltage in the specified direction. It does not create the physical cycle of the signal, but rather assists in achieving a stable display.
Relationships and conditions
The difference in time between two identical states in a cycle is represented by T, and f=1/T is calculated. The peak-to-peak voltage is the difference between the maximum and minimum values.
Real instruments are affected by bandwidth, sampling, probes, and noise. If the trigger level lies outside the signal’s range, the required crossing may not exist and the display may be unstable.
What to observe in the simulation
The horizontal scale is time per division and the vertical scale is voltage per division. Changing scales does not change the signal frequency.
Signals are ideal, with no noise or bandwidth limit. The trigger uses rising edges. Levels outside the amplitude give no trigger. Cursors are adjusted in divisions. Use this simulation; do not reproduce it with real power supplies or wall outlets.
Key relationships and symbols
T = Δt · f = 1/T · Vpp = Vmax − Vmin
| Symbol | Meaning | Unit |
|---|---|---|
| T | Time for one cycle | s |
| Vpp | maximum voltage − minimum voltage | V |
| f | frequency | Hz |
Worked example
What peak-to-peak voltage is measured with cursors 4 div apart at 1 V/div?
4 V
Common misconceptions
- Changing the scale on the time axis causes the waveform to appear narrower, but the actual period of the signal has not changed.